<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1.0">
    <title>长鉴</title>
  </head>
  <style>
    *{
      padding: 0;
      margin: 0;
    }
  </style>
  <script>
    function op (a) {
      alert(1)
    }
  </script>
  <body>
    <div id="app"></div>
  </body>
</html>
